Adjustable height and variable force clamp

ABSTRACT

A quick-acting, spring-pressed clamp adjustable for spring compression clamping force having a body with a lever fulcrummed on a pillar which is heightwise adjustable. A post on the body is also heightwise adjustable for compensating for the adjusted height of the pillar fulcrum point. Thus height adjustment of the post and pillar adjust the height of the lever. A clamp jaw is connected to the weight end of the lever with the jaw thereby being height opening adjustable relative to a workpiece. The post pivotally supports a toggle knee block which is connected by link to the power end of the lever. The knee block is actuated by a handle. A spring supported on the body surrounds the post and an adjustment nut on the body supports the post on the spring. An opposing nut on the post opposes the adjustment nut on the post so that the spring may be pre-compressed under load therebetween to adjust the clamping force as desired without changing the adjusted height of the jaw relative to a workpiece in its open position and without interference in its clamped position.

United States Patent Kulson Oct. 10, 1972 [54] ADJUSTABLE HEIGHT AND[57] ABSTRACT VARIABLE FORCE CLAMP A quick-acting, spring-pressed clampadjustable for [72] Inventor: Walter A. Kulson, 30034 Paul springcompression clamping force having a body with Court, Warren, Mich. 48091a lever fulcrummed on a pillar which is heightwise ad- [22] Filed: May20, 1971 justable. A post on the body is also heightwise adjusta- [211App]. No.: 145,260

[52] US. Cl ..269/228, 269/236 [51] Int. Cl ..B25b l/14, B25b 5/12 [58]Field of Search ..269/196, 198, 201, 204, 221, 269/224, 228, 229, 236

[56] References Cited UNITED STATES PATENTS 2,439,483 4/ 1948 Merriman..269/228 X 2,537,594 l/l95l Lehmann ..269/229 3,31 1,367 3/1967Sendoykas ..269/228 X Primary Examiner-Robert L. SpruillAttorney-William T. Sevald ble for compensating for the adjusted heightof the pi]- lar fulcrum point. Thus height adjustment of the post andpillar adjust the height of the lever. A clamp jaw is connected to theweight end of the lever with the jaw thereby being height openingadjustable relative to a workpiece. The post pivotally supports a toggleknee block which is connected by link to the power end of the lever. Theknee block is actuated by a handle. A spring supported on the bodysurrounds the post and an adjustment nut on the body supports the poston the spring. An opposing nut on the post opposes the adjustment nut onthe post so that the spring may be pre-compressed under loadtherebetween to adjust the clamping force as desired without changingthe adjusted height of the jaw relative to a workpiece in its openposition and without interference in its clamped position.

5 Claim, 3 Drawing Figures ADJUSTABLE HEIGHT AND VARIABLE FORCE CLAMPThis invention relates to a quick-acting, springpressed clamp which isadjustable for spring clamping force and adjustable for opening heightto accommodate various size workpieces.

A primary object of the invention is to provide a clamp which is simplein design and construction, easy to mount on a machine or fixture, andinexpensive to manufacture.

An object of the invention is to provide a clamp having a lever actuatedby a toggle knee block to develop high mechanical clamping force.

An object of the invention is to apply the high clamping force of theclamp through a spring which is adjustable for spring load imposed sothat the clamping force applied to a workpiece is adjustable by varyingthe compression of the spring.

An object of the invention is to provide a clamp jaw slidably mounted onthe clamp body over a substantially long travel to accomodate varioussize workpieces.

An object of the invention is to provide a lever pivotally connected tothe jaw for moving the jaw between its open and clamped positions.

An object of the invention is to provide an adjustable height fulcrumfor the lever for positioning the jaw via the lever at the desiredheight.

An object of the invention is to provide a height-wise adjustable postsupporting the actuating linkage connected to the lever for adjustingthe height of the actuating linkage to compensate for the adjustedheight of the lever and the jaw.

An object of the invention is to provide a spring based on the clampbody and surrounding the post and compression-wise adjustably connectedto the post by an adjusting nut so that the post is based on the bodyvia the spring with the spring adjustably compressable via the nut tovary the spring compression load applied through the clamp to aworkpiece as desired.

These and other objects of the invention will become apparent byreference to the following description of a clamp embodying theinvention taken in connection with the accompanying drawing, in which:

FIG. 1 is a side elevational view of a clamp embodying the invention inoperational position on a machine or fixture in clamping condition on aworkpiece shown in broken lines.

FIG. 2 is an end elevational view of the device seen in FIG. 1 from theright end thereof with the machine or fixture broken away; and

FIG. 3 is a vertical cross-sectional view of the device seen in FIGS. 1and 2 taken on the line 3-3 of FIG. 2, in the open unclamped positionwith the showing of the workpiece deleted.

Referring now to the drawing wherein like numerals refer to like andcorresponding parts throughout the several views, the clamp disclosedtherein to illustrate the invention comprises, a body having transverseapertures for receiving mounting screws 11, 12, and 13. The screws 11-13are threaded in a machine or fixture 14 having an anvil or base 15 underthe body 10. The body 10 has slide ways 16 and 17 attached to the bodyby screws 18. The ways 16 and 17 and the body 10 form a slide channel. Ajaw 20 is slideably positioned in the slide channel against the body 10behind the ways 16 and 17 for movement toward and away from the base 15.

The body has a top 21, a bottom 22, and a channel 23 extendingtherebetween. A fulcrum pillar 24 lies in the channel 23 and projectsabove the top 21 and below the bottom 22. Jam nuts 25 and 26 arethreaded on the pillar 24 and abut the top 21 and bottom 22 of the body10 respectively and secure the pillar 24 relative to the body 10. Theupper end of the pillar 24 has a top aperture. A fulcrum pin 27 lies inthe top aperture of the pillar 24. The upper end of the jaw 20 has anaperture and a pin 28 lies therein.

A lever 30 is fulcrumed in its intermediate position on the pillar 24via the pin 27 with its weight end pivotally connected to the jaw 20 viathe pin 28. The power end of the lever 30 has an aperture receiving apin 31. A push-pull link 32 has an end pivotally connected to the lever30, by the pin 31. A toggle kneeblock 33'is pivotally connected to theother end of the link 32 by a pin 34.

The body 10 has a post bore 40. A threaded post 41 lies in the bore 40and has an upper end equipped with an aperture receiving the pin 42. Thepin 42 pivotally connects the knee-block 33 on the post 41. A spring 43surrounds the post 41 in the bore 40. A heavy washer or plate 44 iswelded on the body 10 at the bore 40. A spring 43 lies in the bore 40,surrounds the post 41, and has a bottom end based on the plate 44. Anadjusting nut 45 is threaded on the post 41 and abuts the top end of thespring 43 in opposition to the plate 44. The post 41 is supportedon thebody 10 via the plate 44, spring 43 and adjusting nut 45. An opposingnut 46 is threaded on the post 41 and abuts the plate 44. The opposingnut 46 prevents upward movement of the post 41. The opposing nut 46 alsoopposes the adjusting nut 45 relative to pre-load compression of thespring 43. An arm or handle 50 is attached to the knee-block 33 andmoves the knee-block 33 to the pivot-point aligned and link 32 extendedclamping position seen in FIGS. 1 and 2 and to the pivot-point cockedand link 32 retracted unclamping position seen in FIG. 3.

The pin 28 interconnecting the weight end of the lever 30 with the jaw20 is undersize relative to the aperture in the lever 30 and/or theaperture in the jaw 20. As these apertures are oversize relative to thepin 28, relative movement is allowed between the lever 30 and the jaw 20in their movement between the clamping position seen in FIG. 1 and theopen position seen in FIG. 3.

In movement of the jaw 20 from the clamping position of FIG. 1 to theopen position of FIG. 3, the pin 28 provides the connecting link betweenthe parts. The pin 28 also initially provides the connecting linkbetween the parts in their movement from the open position of FIG. 3 tothe clamping position of FIG. 1 until the outer end of the lever 30makes contact with the boss on the top of the jaw 20. This contactoccurs about midway in the clamping direction of movement of the parts.Thus during the last portion of the clamping movement, the end of thelever 30 and the boss on the jaw 20 are in abutting engagement andtransfer the entire heavy clamping force between the lever 30 and thejaw 20. Thus the pin 28 is subjected to only light forces in opening andthe first portion of clamping and the lever 30 and jaw 20 directlyengage during the imposition of the heavy clamping forces exerted by themechanism.

The oversize apertures in the jaw 20 and/or lever 30 relative to the pin28 thus allow for relative movement between the lever 30 and jaw 20 toeliminate any binding action therebetween both in the opening andclosing of the jaw 20 and also allow force relief on the pin 28 afterthe lever 30 and jaw 20 directly engage one another in the last portionof movement in the clamping direction.

In use and operation, the linkage is moved to the unclamped positionseen in FIG. 3 and a workpiece 51 positioned on the base 15. Theoperator then moves the handle 50 to the position seen in FIGS. 1 and 2with the toggle knee 33 and link 32 raising the power end of the lever30 and depressing the weight end of the lever 30 which moves the jaw 20downwardly against the workpiece and clamps it against the base 15.

To adjust the clamp device for a different size workpiece than shown,such as a larger workpiece, the operator loosens the jam nut 26 on thepillar 24 and the opposition nut 46 on the post 41. The operator thentightens the jam nut 25 on the fulcrum pillar 24 which raises the lever30 and the jaw 20 to accommodate the larger workpiece. As the oppositionnut 46 is free, this also raises the actuating linkage and post 41 tocompensate for the increased height of the lever 30 and the jaw 20. Theoperator then tightens the jam nut 26 on the pillar 24 to secure thepillar 24, lever 30, and jaw 20 at the adjusted height. The operatorthen tightens the adjusting nut 45 down on the spring 43 to compress thespring 43 against the plate 44 to provide the desired spring loading ofthe spring 43. The operator then tightens the opposition nut 46 to abutthe plate 44 to prevent the post from moving upwardly when the device isin the unclamped condition. This provides a reaction point for raisingthe jaw 20 and prevents the spring 43 under pre-load compressionexerting closing force on the linkage and lever 30 and this allowsretraction on the jaw 20.

The device may be adjusted for desired spring compression load bytightening the adjusting nut 45 down on the spring 43 against thereaction point provided by the opposition nut 46 as both exert force onthe post 41 in opposite directions which force is imposed on the spring43. This provides the adjusted pre-load on the spring 43 prior toclamping. The clamping action of the device further compresses thespring 43 as the post 41 and opposition nut 46 are free to movedownwardly whereas the spring 43 is blocked against further downwardmovement by the plate 44. Thus the clamping force exerted on theworkpiece 51 by the jaw 20 is a combination of the mechanical advantageof the lever 30 and the toggle knee-block 33, the strength of the spring43, and the adjusted pre-load imposed on the spring 43. Thus theoperator may adjust the force imposed on the workpiece by selecting aspring of desired strength and adjusting the pre-load compression of thespring as stated.

In use the jaw is quickly resiliently spring-pressed against theworkpiece with the desired force by moving the handle 50 to the clampingposition and quickly released by movement of the handle in the oppositedirection.

The appended claims define the scope of the invention.

I claim:

1. A quick acting combination toggle and lever clamp capable ofadjustable spring compression to vary the clamping force as desired andadjustable for opening height to accommodate various size workpieces,comprising;

a body having a slide way, a fulcrum pillar channel,

and a post bore,

a clamp jaw in said body slide way,

a lever having weight and power ends and an intermediate fulcrumportion; said lever being pivotally mounted on said fulcrum pillar inits said intermediate fulcrum portion and pivotally connected to saidclamp jaw at its said weight end;

a push-pull link having one end pivotally connected to said power end ofsaid lever and an extending end,

a toggle knee block having two pivot points with one said pivot pointpivotally connected to said extending end of said link,

a post having top and bottom ends lying in said post bore of said bodywith its top end pivotally connected to said other pivot point of saidknee block; said bottom end of said post being freely slideable in saidpost bore;

a spring surrounding said post in said bore; said spring having top andbottom ends;

said body having spring supporting means abutting said bottom end ofsaid spring;

said post being threaded for receiving a nut thereon;

an adjustment nut threaded on said post and engaging said top end ofsaid spring; and

an actuator handle on said knee block;

movement of said handle in one direction cocking said knee block andmoving said lever power end via said link toward said body to raise saidweight end of said lever to retract said jaw away from a workpiece;

manual movement of said handle in the other direction moving said powerend of said lever via said link away from said body to depress saidweight end of said lever to advance said jaw toward a workpiece;

said post being supported on said spring via said adjustment nut;

said adjustment nut being adjustable on said post relative to saidspring to increase and decrease the compression of said spring toincrease and decrease the resulting weight force of said jaw against aworkpiece in the advanced clamping position of said jaw.

2. In a device as set forth in claim 1, said post having a threaded endextending beyond said spring supporting abutment means on said body; andan opposing nut threaded on said threaded projecting end of said post;said opposing nut abutting said abutment means;

said opposing nut acting in opposition to said spring adjustment nut topermit said spring adjustment nut to exert spring compression force onsaid spring to pre-load said spring as desired without pre-load affecton the open head space, shut engagement, and travel of said jaw.

3. In a device as set forth in claim 1, said body having a top and abottom; said pillar being threaded;

a base nut on said pillar engaging said top of said body therebysupporting said pillar against inward movement relative to said body,and

a jam nut on said pillar engaging said bottom of said body supportingsaid pillar against outward movement of said pillar relative to saidbody; said pillar being raisable and lowerable by said nuts toselectively raise and lower its fulcrum point to adjust the height ofsaid lever and jaw relative to a workpiece;

said spring adjustment nut being adjustable relative to said post toalso selectively raise and lower said post on said spring at said powerend of said lever to compensate for height adjustment of said fulcrumpoint of said lever at said pillar and to compress said spring asdesired at the adjusted height.

4. In a device as set forth in claim 1, said clamp jaw and said leverhaving aligned apertures and a pin lying in said apertures pivotallyinterconnecting said clamp jaw and said lever;

said pin being undersize relative to at least one aperture in said clampjaw and said lever to allow relative movement therebetween to eliminatebinding during clamping and opening movement;

said lever having an outer end and said clamp jaw having a top portionengaging one another in the clamping direction of movement to directlytransfer force between said lever and said clamp jaw and to relieveheavy force imposition on said pm.

5. In a device as set forth in claim 1, said post having a threaded endextending beyond said spring supporting abutment means on said body; andan opposing nut threaded on said threaded projecting end of said post;said opposing nut abutting said abutment means;

said opposing nut acting in opposition to said spring adjustment nut topermit said spring adjustment nut to exert spring compression force onsaid spring to pre-load said spring as desired without pre-load affecton the open head space, shut engagement, and travel of said jaw;

a base nut on said pillar engaging said top of said body therebysupporting said pillar against inward movement relative to said body;

a jam nut on said pillar engaging said bottom of said body supportingsaid pillar against outward movement of said pillar relative to saidbody; said pillar being raisable and lowerable by said nuts toselectively raise and lower its fulcrum point to adjust the height ofsaid lever and jaw relative to a workpiece;

said spring adjustment nut being adjustable relative to said post toalso selectively raise and lower said post on said spring at said powerend of said lever to compensate for height adjustment of said fulcrumpoint of said lever at said pillar and to compress said spring asdesired at the adjusted height;

said clamp jaw and said lever having aligned apertures and a pin lyingin said apertures pivotally interconnecting said clamp jaw and saidlever;

said pin being undersize relative to at least one aperture in said clampjaw and said lever to allow relative movement therebetween to eliminatebinding during clamping and opening movement;

said lever having on outer end and said clamp jaw having a top portionengaging one another in the clamping direction of movement to directlytransfer force between said lever and said clamp jaw to relieve heavyforce imposition on said pin.

1. A quick acting combination toggle and lever clamp capable ofadjustable spring compression to vary the clamping force as desired andadjustable for opening height to accommodate various size workpieces,comprising; a body having a slide way, a fulcrum pillar channel, and apost bore, a clamp jaw in said body slide way, a lever having weight andpower ends and an intermediate fulcrum portion; said lever beingpivotally mounted on said fulcrum pillar in its said intermediatefulcrum portion and pivotally connected to said clamp jaw at its saidweight end; a push-pull link having one end pivotally connectEd to saidpower end of said lever and an extending end, a toggle knee block havingtwo pivot points with one said pivot point pivotally connected to saidextending end of said link, a post having top and bottom ends lying insaid post bore of said body with its top end pivotally connected to saidother pivot point of said knee block; said bottom end of said post beingfreely slideable in said post bore; a spring surrounding said post insaid bore; said spring having top and bottom ends; said body havingspring supporting means abutting said bottom end of said spring; saidpost being threaded for receiving a nut thereon; an adjustment nutthreaded on said post and engaging said top end of said spring; and anactuator handle on said knee block; movement of said handle in onedirection cocking said knee block and moving said lever power end viasaid link toward said body to raise said weight end of said lever toretract said jaw away from a workpiece; manual movement of said handlein the other direction moving said power end of said lever via said linkaway from said body to depress said weight end of said lever to advancesaid jaw toward a workpiece; said post being supported on said springvia said adjustment nut; said adjustment nut being adjustable on saidpost relative to said spring to increase and decrease the compression ofsaid spring to increase and decrease the resulting weight force of saidjaw against a workpiece in the advanced clamping position of said jaw.2. In a device as set forth in claim 1, said post having a threaded endextending beyond said spring supporting abutment means on said body; andan opposing nut threaded on said threaded projecting end of said post;said opposing nut abutting said abutment means; said opposing nut actingin opposition to said spring adjustment nut to permit said springadjustment nut to exert spring compression force on said spring topre-load said spring as desired without pre-load affect on the open headspace, shut engagement, and travel of said jaw.
 3. In a device as setforth in claim 1, said body having a top and a bottom; said pillar beingthreaded; a base nut on said pillar engaging said top of said bodythereby supporting said pillar against inward movement relative to saidbody, and a jam nut on said pillar engaging said bottom of said bodysupporting said pillar against outward movement of said pillar relativeto said body; said pillar being raisable and lowerable by said nuts toselectively raise and lower its fulcrum point to adjust the height ofsaid lever and jaw relative to a workpiece; said spring adjustment nutbeing adjustable relative to said post to also selectively raise andlower said post on said spring at said power end of said lever tocompensate for height adjustment of said fulcrum point of said lever atsaid pillar and to compress said spring as desired at the adjustedheight.
 4. In a device as set forth in claim 1, said clamp jaw and saidlever having aligned apertures and a pin lying in said aperturespivotally interconnecting said clamp jaw and said lever; said pin beingundersize relative to at least one aperture in said clamp jaw and saidlever to allow relative movement therebetween to eliminate bindingduring clamping and opening movement; said lever having an outer end andsaid clamp jaw having a top portion engaging one another in the clampingdirection of movement to directly transfer force between said lever andsaid clamp jaw and to relieve heavy force imposition on said pin.
 5. Ina device as set forth in claim 1, said post having a threaded endextending beyond said spring supporting abutment means on said body; andan opposing nut threaded on said threaded projecting end of said post;said opposing nut abutting said abutment means; said opposing nut actingin opposition to said spring adjustment nut to permit said springadjustment nut to exert spring compression force on said spring topre-load said spring as desired without pre-load affect on the open headspace, shut engagement, and travel of said jaw; a base nut on saidpillar engaging said top of said body thereby supporting said pillaragainst inward movement relative to said body; a jam nut on said pillarengaging said bottom of said body supporting said pillar against outwardmovement of said pillar relative to said body; said pillar beingraisable and lowerable by said nuts to selectively raise and lower itsfulcrum point to adjust the height of said lever and jaw relative to aworkpiece; said spring adjustment nut being adjustable relative to saidpost to also selectively raise and lower said post on said spring atsaid power end of said lever to compensate for height adjustment of saidfulcrum point of said lever at said pillar and to compress said springas desired at the adjusted height; said clamp jaw and said lever havingaligned apertures and a pin lying in said apertures pivotallyinterconnecting said clamp jaw and said lever; said pin being undersizerelative to at least one aperture in said clamp jaw and said lever toallow relative movement therebetween to eliminate binding duringclamping and opening movement; said lever having on outer end and saidclamp jaw having a top portion engaging one another in the clampingdirection of movement to directly transfer force between said lever andsaid clamp jaw to relieve heavy force imposition on said pin.